Output Regulation Research Articles

Adaptive output regulation for a one-dimensional wave system with variable coefficients subject to unknown biased harmonic disturbances

Adaptive output regulation for a one-dimensional wave system with variable coefficients subject to unknown biased harmonic disturbances

Observer-based resilient cooperative output regulation for nonlinear multiagent systems with time-varying parameters and DoS attacks

This paper aims to address the cooperative output regulation (COR) problem of nonlinear multiagent systems (MASs) with time-varying parameters under denial-of-service (DoS) attacks. First, to address the challenges of unavailable leader signals and non-differentiability issue caused by the DoS attacks, a class of first-order low-pass filters is employed to develop a novel distributed resilient observer, which accurately estimate the exosystem state with the existence of high-order derivatives. Then, by viewing the output of observer as the reference signal, a distributed resilient controller is designed for each follower to address the reference-tracking problem. By introducing a smooth function with positive integrable time-varying function, novel adaptive laws are developed and incorporated with the controller design to effectively compensate for the unknown time-varying parameters. By utilising Lyapunov stability theory, the asymptotic convergence of output regulation error can be ensured. Finally, simulation results are conducted to verify the validity of the designed method.

The study of active support for energy storage system in system frequency regulation

Abstract As the penetration of new energy sources increases, the proportion of traditional energy units continues to decline, reducing the inertia and primary frequency regulation capability of the power system. Therefore, exploring the frequency support capabilities of energy storage systems with low inertia is crucial. Based on this, this paper first proposes an active frequency support method for energy storage system based on a Voltage Source Virtual Synchronous Generator (VSG), aiming to enhance system inertia and reduce response delay. Based on this issue, a parameter tuning optimization selection model based on the Transient Search Optimization (TSO) algorithm is proposed to determine the optimal power output and best frequency regulation parameters for the energy storage system. Finally, the model proposed in this paper is applied to the IEEE 14-bus system to verify its effectiveness.

Cooperative Output Regulation for Continuous-Time Linear Periodic Systems

Cooperative Output Regulation for Continuous-Time Linear Periodic Systems

Collisions-Free Distributed Cooperative Output Regulation of Nonlinear Multiagent Systems

Collisions-Free Distributed Cooperative Output Regulation of Nonlinear Multiagent Systems

An Internal Model Approach to Cooperative Output Regulation Over Switching Graphs

An Internal Model Approach to Cooperative Output Regulation Over Switching Graphs

Distributed Neuroadaptive Formation Control for Aerial Base Station-Assisted Hovercraft Systems with Mixed Disturbances

Effectively addressing the formation control of ABS-assisted hovercraft systems with heterogeneities, unavailable leaders’ convex combination states, nonlinearities, and mixed disturbances poses significant challenges. This paper proposes a distributed neuroadaptive formation tracking strategy of ABS-assisted hovercraft systems for the first time, where aerial base stations (ABSs) are composed of unmanned aerial vehicles (UAVs) for data distribution and computation offloading. Firstly, UAVs are designed to track the virtual-leader while shaping a fixed formation, and the observer is devised for each follower hovercraft to estimate the convex combination states of UAVs. Then, output regulation equations are employed to transform heterogeneous systems into a compact form via the Kronecker product, while neural networks (NNs) are introduced to compensate for model nonlinearities. Furthermore, based on random differential equations (RDEs) combined with Lyapunov theory, the noise-to-state practical stability in probability (NSPS-P) property of the error dynamics under mixed disturbances can be obtained. Finally, simulation examples demonstrate that the outputs of follower hovercrafts rapidly achieve a time-varying formation and rotate around convex combination states of leader UAVs simultaneously.

Nicotinic signaling stimulates glucagon secretion in mouse and human pancreatic α-cells.

Smoking is widely regarded as a risk factor for type 2 diabetes, as nicotine contributes to insulin resistance by desensitizing the insulin receptors in muscle, liver, or fat. Little is known, however, about the immediate regulation of islet hormonal output by nicotine, an agonist of ionotropic cholinergic receptors. We investigated this by imaging cytosolic Ca2+ dynamics in mouse and human islets using confocal microscopy and measuring glucagon secretion in response to the alkaloid from isolated mouse islets. Nicotine acutely stimulated cytosolic Ca2+ in glucagon-secreting α-cells but not in insulin-secreting β-cells. The 2.8±0.5-fold (p<0.05) increase in the Ca2+, observed in >70% of α-cells, correlated well with a 2.5±0.3-fold stimulation of glucagon secretion. Nicotine-induced elevation of cytosolic Ca2+ relied on the influx from the extracellular compartment rather than the release of the cation from intracellular depots. Metabotropic cholinergic signaling, monitored at the level of intracellular diacylglycerol, was limited to 69% of α-cells vs 94% of β-cells. We conclude that parasympathetic regulation of pancreatic islet hormone release utilizes different signaling pathways in β- (metabotropic) and α-cells (metabotropic and ionotropic), resulting in the finetuning of the ACh-induced glucagon exocytosis. Sustained nicotinic stimulation is, therefore, likely to attenuate insulin sensitivity by increasing glucagon release.

A Coordinated Emergency Frequency Control Strategy Based on Output Regulation Approach for an Isolated Industrial Microgrid

Constructing isolated industrial microgrids with wind power is beneficial for improving the economic benefits of high-energy-consuming production, such as the electrolytic aluminum industry. Due to the specialized structure of industrial microgrids and the unique characteristics of the electrolytic aluminum load (EAL), the common emergency frequency control methods do not apply to the specific operational requirements of isolated industrial microgrids. Since EALs have huge regulating capacities and fast responses, this paper proposes a coordinated emergency frequency control scheme to deal with power disturbances in isolated industrial microgrids. The coordinated frequency control model of an industrial microgrid considering demand-side participation is derived. With the help of output regulation theory, a practical, feasible coordinated frequency controller is designed by introducing frequency deviation and power disturbance as feedback control signals. The proposed control scheme achieves reserve power distribution between the generation and demand sides. The microgrid frequency can be maintained within a permitted range in the presence of large power imbalances. The simulation results conducted in an actual isolated industrial microgrid validate the effectiveness and dynamic performance of the proposed control scheme.

Anti-asynchrony output regulation for switched systems under switching-Q-learning event-triggering against DoS attacks

Anti-asynchrony output regulation for switched systems under switching-Q-learning event-triggering against DoS attacks

Pinning control design for the output regulation of Boolean networks

In previous studies, the output regulation problem (ORP) of Boolean networks (BNs) is usually studied by the augmented system method, however, the state transition matrix dimension of augmented system is growing exponentially as the number of network nodes increases. To reduce the computational complexity, a new method to solve the ORP is adopted in this paper. Firstly, the relationship among the attractors of two BNs and their augmented system is studied, based on which, the ORP is converted into the set stabilisation problem of the original BN, and some necessary and sufficient conditions are given to detect the solvability of the ORP. Secondly, a pinning control for the ORP is considered according to the attractors of the original BNs, and an algorithm to design this kind of controls is provided. Finally, a practical example of signal transduction network is given to illustrate the effectiveness of the method in this paper.

Robust Predefined Output Containment for Heterogeneous Nonlinear Multiagent Systems Under Unknown Nonidentical Leaders' Dynamics.

This article discusses the robust predefined output containment (RPOC) control problem for heterogeneous nonlinear multiagent systems having multiple uncertain nonidentical leaders. In order to solve this problem, a new kind of distributed observer-based RPOC control framework is presented. First, for obtaining the information of nonidentical leaders' dynamics, including uncertain parameters in leaders' system matrices, output matrices, states, and outputs, four kinds of adaptive observers are constructed in a fully distributed form without any knowledge of the dynamics of nonidentical leaders, exactly. Second, on the basis of adaptive learning technique, a new RPOC controller is then developed by using the presented observers, where the adaptive observers can make up for the uncertain parameter in followers' dynamics, and the solutions of output regulation equations can be obtained adaptively by the developed adaptive strategy. Furthermore, with the help of the output regulation method and Lyapunov stability theory, the RPOC criteria for the considered system under unknown nonidentical leaders' dynamics are derived from the constructed controller. Finally, a simulation example is provided to demonstrate the effectiveness of the proposed RPOC controller.

Funnel-Based Cooperative Output Regulation Control for Uncertain Nonlinear Multiagent Systems Under Input Saturation

Funnel-Based Cooperative Output Regulation Control for Uncertain Nonlinear Multiagent Systems Under Input Saturation

Adaptive Disturbance Suppression Output Regulation for Switched Systems With Multi-Source Disturbances

Adaptive Disturbance Suppression Output Regulation for Switched Systems With Multi-Source Disturbances

Optimal Output Regulation for EV Dynamic Wireless Charging System via Internal Model-Based Control

Optimal Output Regulation for EV Dynamic Wireless Charging System via Internal Model-Based Control

Fully distributed dynamic event-triggered reliable COR of nonlinear MASs with communication link faults and actuator faults for directed graphs

The issue of fault-tolerant cooperative output regulation (COR) for nonlinear uncertain multiagent systems (MASs) under communication link faults (LFs) and actuator faults is investigated in this paper. This is the first attempt to study the fault-tolerant COR problem for the aforementioned MASs under directed graphs. To handle unknown LFs and avoid using global information, adaptive event-triggered (ET) observers are designed to estimate the exosystem state. That is, resilience against communication LFs is translated to distributed observer design. To overcome the “explosion of complexity” and obtain asymptotically stable results, dynamic surface control (DSC) techniques are introduced. Unlike existing linear DSC techniques that generate boundary layer errors, this paper introduces nonlinear filters with compensation terms into dynamic surfaces to eliminate boundary layer errors. Adaptive control laws that can achieve asymptotically regulated output are then developed based on the improved DSC techniques. It is shown that the developed control strategy can achieve fault-tolerant COR for the considered MASs. Additionally, the implemented dynamic event-triggered mechanism (ETM) ensures strictly positive minimum event-triggered intervals (ETIs) and avoids Zeno behavior. Finally, a practical simulation example reveals the effectiveness of the suggested scheme.

Extending the design space of minimized VA rating inductive wireless power transfer links operating in restricted sub-resonant frequency region with constant current output

Wireless power transfer systems are typically required to operate under varying geometrical positioning (vertical distance, misalignment) between the transmitter and receiver coils while supporting a load with non-constant characteristics. This creates the need for robust systems that can operate over a range of coupling coefficients under time-varying load. Widespread control methods utilized to support such an operation typically suffer from volt-ampere (VA) over-rating of the inductive wireless power transfer link (IWPTL) transmitter. Sub-resonant frequency control has proven to be an effective solution to this problem, attaining robust operation and minimized transmitter VA rating by utilizing operational frequency as the control variable for system output regulation under above-mentioned constraints. However, allowed operating frequency range is usually restricted in practical applications (e.g. to 79 kHz–90 kHz by SAE J2954 EV charging standard), limiting the misalignment tolerance of sub-resonant control method. Recently, extension of the classical sub-resonant control methodology was proposed in order to overcome this limitation. However, no clear guidelines were given for designing practical IWPTLs operating under extended sub-resonant control. To this end, this work bridges the gap between academical findings and practical applications by establishing generalized guidelines for designing sub-resonant controlled series-series (SS) compensated IWPTL with minimized transmitter VA rating, allowing to maximize misalignment tolerance under given operating frequency and output voltage ranges. The proposed methodology is accurately validated by simulations and experiments, demonstrate close correlation with analytical predictions. Experimental framework reveals that IWPTL operating under extended sub-resonant control methodology attains 50 % increase of tolerable coupling coefficients range compared to a classical system designed to operate under sub-resonant control under identical operating conditions while achieving nearly similar DC-to-DC efficiency.

CheB localizes to polar receptor arrays during repellent adaptation.

Adaptation of the response to stimuli is a fundamental process for all organisms. Here, we show that the adaptation enzyme CheB methylesterase of Escherichia coli assembles to the ON state receptor array after exposure to the repellent l-isoleucine and dissociates from the array after adaptation is complete. The duration of increased CheB localization and the time of highly clockwise-biased flagellar rotation were similar and depended on the strength of the stimulus. The increase in CheB at the receptor array and the decrease in cytoplasmic CheB were both ~100 molecules, which represents 15 to 20% of the total cellular content of CheB. We confirmed that the main binding site for CheB in the ON state array is the P2 domain of phosphorylated CheA, with a second minor site being the carboxyl-terminal pentapeptide of the serine chemoreceptor. Thus, we have been able to quantify the regulation of the signal output of the receptor array by the intracellular dynamics of an adaptation enzyme.

Adaptive output feedback time‐varying formation tracking of multi‐agent system with a leader of unknown input

AbstractThis paper researches the time‐varying formation tracking (TVFT) problem of linear multi‐agent systems (MASs). By designing a compensator, the problem of time‐varying formation can be considered as the output regulation problem. Thereby, the distributed output feedback controller combined with an adaptive technique is proposed. With this controller, follower agents achieve the desired time‐varying formation and follow the trajectory of the leader agent. Furthermore, extending the designed controller to the case where the leader agent equips with unknown control input. Using Lyapunov stability theory, it is demonstrated that under proper conditions the given protocol is implementable. Simulation example is presented at the end of the paper to illustrate the effectiveness of designed control mechanism.

Robust internal model‐based control for linear‐time‐invariant systems

AbstractThis article addresses robust output regulation for systems affected by disturbances generated by an uncertain exosystem as well as matched external disturbances. The robustness of the feedback loop is achieved by combining internal model based control with sliding mode control, resulting in a structurally simple controller. The design of the proposed controller is presented first for the full information problem, that is, the disturbances generated by the exosystem and the state‐information is available for the control algorithm. This requirement is relaxed in the second step of the controller design, where the observer‐based robust output feedback‐loop structure is developed. Results from a comparative simulation study are presented to illustrate the advantages and the effectiveness of the proposed controller concept.